Add elements of given arrays with given constraints

Given two integer arrays, add their elements into third array by satisfying following constraints –

1. Addition should be done starting from 0th index of both arrays.
2. Split the sum if it is a not a single digit number and store the digits in adjacent locations in output array.
3. Output array should accommodate any remaining digits of larger input array.

Examples:

Input:
a = [9, 2, 3, 7, 9, 6]
b = [3, 1, 4, 7, 8, 7, 6, 9]
Output:
[1, 2, 3, 7, 1, 4, 1, 7, 1, 3, 6, 9]

Input:
a = [9343, 2, 3, 7, 9, 6]
b = [34, 11, 4, 7, 8, 7, 6, 99]
Output:
[9, 3, 7, 7, 1, 3, 7, 1, 4, 1, 7, 1, 3, 6, 9, 9]

Input:
a = []
b = [11, 2, 3 ]
Output:
[1, 1, 2, 3 ]

Input:
a = [9, 8, 7, 6, 5, 4, 3, 2, 1]
b = [1, 2, 3, 4, 5, 6, 7, 8, 9]
Output:
[1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0]

Difficulty Level: Rookie

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

The idea is very simple. We maintain an output array and run a loop from the 0th index of both arrays. For each iteration of loop, we consider next elements in both arrays and add them. If the sum is greater than 9, we push the individual digits of the sum to output array else we push the sum itself. Finally we push the remaining elements of larger input array to output array.

Below is the implementation of above idea –

C++

 // C++ program to add two arrays following given // constraints #include using namespace std;    // Function to push individual digits of a number // to output vector from left to right void split(int num, vector &out) {     vector arr;     while (num)     {         arr.push_back(num%10);         num = num/10;     }     // reverse the vector arr and append it to output vector     out.insert(out.end(), arr.rbegin(), arr.rend()); }    // Function to add two arrays keeping given // constraints void addArrays(int arr1[], int arr2[], int m, int n) {     // create a vector to store output     vector out;        // maintain a variable to store current index in     // both arrays     int i = 0;        // loop till arr1 or arr2 runs out     while (i < m && i < n)     {         // read next elements from both arrays and         // add them         int sum = arr1[i] + arr2[i];            // if sum is single digit number         if (sum < 10)             out.push_back(sum);            else         {             // if sum is not a single digit number, push             // individual digits to output vector             split(sum, out);         }            // increment to next index         i++;     }        // push remaining elements of first input array     // (if any) to output vector     while (i < m)         split(arr1[i++], out);        // push remaining elements of second input array     // (if any) to output vector     while (i < n)         split(arr2[i++], out);        // print the output vector     for (int x : out)         cout << x << " "; }    // Driver code int main() {     int arr1[] = {9343, 2, 3, 7, 9, 6};     int arr2[] = {34, 11, 4, 7, 8, 7, 6, 99};        int m = sizeof(arr1) / sizeof(arr1);     int n = sizeof(arr2) / sizeof(arr2);        addArrays(arr1, arr2, m, n);        return 0; }

Java

 // Java program to add two arrays following given  // constraints  import java.util.Vector;    class GFG {        // Function to push individual digits of a number     // to output vector from left to right     static void split(int num, Vector out)      {         Vector arr = new Vector<>();         while (num > 0)         {             arr.add(num % 10);             num /= 10;         }            // reverse the vector arr and         // append it to output vector         for (int i = arr.size() - 1; i >= 0; i--)             out.add(arr.elementAt(i));     }        // Function to add two arrays keeping given     // constraints     static void addArrays(int[] arr1, int[] arr2,                           int m, int n)      {            // create a vector to store output         Vector out = new Vector<>();            // maintain a variable to store         //  current index in both arrays         int i = 0;            // loop till arr1 or arr2 runs out         while (i < m && i < n)          {                // read next elements from both arrays              // and add them             int sum = arr1[i] + arr2[i];                // if sum is single digit number             if (sum < 10)                 out.add(sum);             else                    // if sum is not a single digit number,                  // push individual digits to output vector                 split(sum, out);                // increment to next index             i++;         }            // push remaining elements of first input array         // (if any) to output vector         while (i < m)             split(arr1[i++], out);            // push remaining elements of second input array         // (if any) to output vector         while (i < n)             split(arr2[i++], out);            // print the output vector         for (int x : out)             System.out.print(x + " ");     }        // Driver Code     public static void main(String[] args)      {         int[] arr1 = { 9343, 2, 3, 7, 9, 6 };         int[] arr2 = { 34, 11, 4, 7, 8, 7, 6, 99 };            int m = arr1.length;         int n = arr2.length;            addArrays(arr1, arr2, m, n);     } }    // This code is contributed by // sanjeev2552

Output:

9 3 7 7 1 3 7 1 4 1 7 1 3 6 9 9

Time complexity of above solution is O(m + n) as we traverses both arrays exactly once.

This article is contributed by Aditya Goel. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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Improved By : sanjeev2552

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